The Effect of Intradialytic Exercise on Postural Abnormalities

Official title

Effects of Supervised Intradialytic Exercise Program on Postural Abnormalities in Maintenance Hemodialysis Patients: A Randomized Controlled Trial

Overview

This randomized, assessor-blinded controlled trial will evaluate the preliminary efficacy and safety of a 12-week supervised intradialytic multimodal exercise program for improving postural abnormalities in adults receiving maintenance hemodialysis. Participants will be randomized to either supervised intradialytic exercise plus usual care or usual care alone. The exercise program will be performed three times per week during scheduled hemodialysis sessions and will include postural correction exercises, resistance-band strengthening, core stabilization, stretching, breathing exercises, and seated aerobic cycling. The primary outcome will be change in thoracic kyphosis angle from baseline to Week 12. Secondary outcomes will include craniovertebral angle, balance, mobility, functional exercise capacity, gait speed, physical activity level, adherence, and adverse events. The findings may provide preliminary evidence on the feasibility, safety, and potential clinical value of incorporating postural correction exercises into routine hemodialysis care.

Detailed description

Falls represent one of the most consequential complications in patients with end-stage renal disease (ESRD), with approximately 25% of dialysis patients experiencing at least one fall annually. Fall-related injuries in this population, including hip fractures, vertebral fractures, and joint dislocations, contribute to significant functional deterioration, diminished quality of life, restricted mobility, and increased healthcare expenditure. Among the many factors driving this fall burden, postural abnormalities have emerged as clinically significant yet persistently underinvestigated contributors. In particular, thoracic hyperkyphosis and forward head posture (FHP) are now recognized as highly prevalent structural deformities in dialysis patients that directly impair postural stability, physical function, and overall safety.

The clinical impact of thoracic hyperkyphosis and FHP extends across multiple physiological domains. Hyperkyphosis, characterized by excessive posterior curvature of the thoracic spine, displaces the body's center of gravity anteriorly, impairing postural control and forcing compensatory adaptations in the lumbar spine and hips. When these compensatory mechanisms are overwhelmed, as is common in the context of the sarcopenia and muscle weakness that accompany ESRD, hyperkyphosis leads to impaired gait, reduced walking speed, diminished balance, and substantially heightened fall susceptibility. Beyond its musculoskeletal effects, thoracic hyperkyphosis restricts thoracic cage mobility, reduces vital capacity, and compromises cardiopulmonary function.

FHP, defined as anterior displacement of the head relative to the shoulder plumb line in the sagittal plane, generates disproportionate loading of the posterior cervical musculature and disrupts the normal biomechanics of the cervical spine. This misalignment reduces both static and dynamic balance by destabilizing the vestibular and proprioceptive feedback systems that depend on neutral cervical alignment. FHP has been associated with increased postural sway and instability in older adults, as well as altered thoracic shape and impaired respiratory function through weakening of the accessory breathing musculature. Critically, hyperkyphosis and FHP are biomechanically coupled: as thoracic kyphosis increases, compensatory anterior head translation increases proportionally to maintain horizontal gaze, creating a self-reinforcing cycle of progressive postural dysfunction and functional decline.

Despite the scale and clinical consequences of this problem, effective corrective strategies for dialysis patients remain largely untested. Evidence from general and older adult populations, however, strongly supports the role of targeted exercise in correcting both hyperkyphosis and FHP. Combined strengthening and stretching exercise programs, specifically targeting the thoracic extensors, scapular stabilizers, and deep cervical flexors while stretching the shortened anterior chain muscles, are found to produce significant reductions in kyphosis angle and improvements in craniovertebral angle across populations with postural deformities. These findings indicate that exercise-based postural correction is not only feasible but reliably effective in older adults with comparable musculoskeletal profiles to dialysis patients, making translation to the ESRD population a logical and clinically justified step.

The key challenge lies in delivering such exercise to a population with significant barriers to participation in community or home-based programs, including transportation dependence, fatigue, and medically complex comorbidities. Intradialytic exercise (IDE), supervised physical activity performed during scheduled hemodialysis sessions, offers a uniquely practical solution. By embedding exercise within the unavoidable treatment time of dialysis, IDE eliminates the need for additional healthcare visits, ensures direct professional supervision, and capitalizes on the structure of the dialysis schedule to provide consistent physical stimulation.

Despite this accumulating evidence, no published trial has specifically examined the effect of intradialytic exercise on the structural postural abnormalities of thoracic hyperkyphosis and FHP in hemodialysis patients. The present randomized controlled trial therefore aims to determine whether a 12-week supervised, multimodal intradialytic exercise program can improve spinal and cervical postural alignment, dynamic balance, physical function, and health-related quality of life in hemodialysis patients, providing the evidence needed to justify integrating postural correction into standard dialysis care.

Interventions

• Behavioral Supervised Intradialytic Multimodal Exercise Program
  Exercises include thoracic extension, scapular retraction, deep cervical flexor activation, pectoral stretching, seated rowing, shoulder external rotation, seated knee extension, hip flexion, ankle pumps, and cycle ergometry. Resistance exercises will be performed for 1-3 sets of 10-15 repetitions and progressed every two weeks according to RPE, tolerance, and absence of adverse symptoms. Exercise will be stopped if the participant develops chest pain, severe dyspnea, dizziness, nausea, muscle c

Primary outcome measures

• Change in Thoracic Kyphosis Angle From Baseline to Week 12 [Time frame: Pre-test (Baseline) and 3 Months Later (Post-test, Week 12)]
• Change in craniovertebral angle, measured in degrees, from baseline to Week 12 [Time frame: Pre-test (Baseline) and 3 Months Later (Post-test, Week 12)]

Secondary outcome measures (5)

• Change in Timed Up and Go Test (TUG) From Baseline to Week 12 [Time frame: Pre-test (Baseline) and 3 Months Later (Post-test, Week 12)]
• Change in Berg Balance Scale Score From Baseline to Week 12 [Time frame: Pre-test (Baseline) and 3 Months Later (Post-test, Week 12)]
• Change in Six-Minute Walk Distance From Baseline to Week 12 [Time frame: Pre-test (Baseline) and 3 Months Later (Post-test, Week 12)]
• Change in Gait Speed From Baseline to Week 12 [Time frame: Pre-test (Baseline) and 3 Months Later (Post-test, Week 12)]
• Change in LoPAQ Total Physical Activity Score From Baseline to Week 12 [Time frame: Pre-test (Baseline) and 3 Months Later (Post-test, Week 12)]

Eligibility criteria

Inclusion criteria

• Age 18-80 years
• Diagnosed with ESRD and receiving stable maintenance hemodialysis for at least 3 months at the participating center, with a dialysis frequency of three sessions per week
• Confirmed presence of at least one postural abnormality (hyperkyphosis ≥53° in women or ≥55° in men, or CVA <53°) assessed at screening
• Written informed consent obtained, indicating decision-making capacity and willingness to participate
• Medical clearance from attending nephrologist to participate in supervised exercise during dialysis
• Ability to sit upright in a dialysis chair and perform seated or supported standing exercises
• Ability to communicate in Persian and understand study instructions

Exclusion criteria

• Unstable cardiovascular status, including recent (within 3 months) myocardial infarction, unstable angina, decompensated congestive heart failure (NYHA Class III-IV), or uncontrolled arrhythmia
• Active infection, acute febrile illness, or acute medical condition requiring hospitalization
• Hemodynamic instability defined as systolic blood pressure <90 mmHg or >200 mmHg, or severe orthostatic hypotension, at screening or prior to exercise sessions
• Uncontrolled diabetes mellitus with labile glycemic control (blood glucose <4 mmol/L or >22 mmol/L at dialysis session start)
• Severe musculoskeletal pain at rest or with minimal activity (Numeric Pain Rating Scale ≥7/10) that would preclude exercise participation
• Inability to perform seated exercises, walk independently, or maintain upright posture; severe neurological disability
• Recent fracture (within 6 months) of vertebral column, pelvis, or lower extremities
• Severe peripheral neuropathy or vascular disease (ABI <0.6) precluding lower limb exercise
• Dyspnea at rest or with activities of daily living corresponding to NYHA Class IV
• Participation in a structured exercise program targeting postural correction, resistance, or balance training ≥3 times per week in the preceding 3 months
• Severe cognitive impairment (MMSE <18) preventing informed consent or adherence to exercise instruction
• Pregnancy or planned pregnancy during the study period
• Life expectancy <6 months as determined by the attending nephrologist
• Scheduled kidney transplantation within the study period

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Supportive care

Study locations

Iran · 1 center

• Pardis specialized wellness institute — Isfahan

Publications

• Tabibi MA, Cheema B, Salimian N, Correa HL, Ahmadi S. The effect of intradialytic exercise on dialysis patient survival: a randomized controlled trial. BMC Nephrol. 2023 Apr 17;24(1):100. doi: 10.1186/s12882-023-03158-6. PMID 37069527
• Greenwood SA, Young HML, Briggs J, Castle EM, Walklin C, Haggis L, Balkin C, Asgari E, Bhandari S, Burton JO, Billany RE, Bishop NC, Bramham K, Campbell J, Chilcot J, Cooper NJ, Deelchand V, Graham-Brown MPM, Hamilton A, Jesky M, Kalra PA, Koufaki P, McCafferty K, Nixon AC, Noble H, Saynor Z, Taal MW, Tollit J, Wheeler DC, Wilkinson TJ, Worboys H, Macdonald JH. Evaluating the effect of a digital h PMID 37968170
• Chae TS, Kim DS, Ko MH, Won YH. Effect of Pre- and Post-Dialysis Exercise on Functional Capacity Using Portable Ergometer in Chronic Kidney Disease Patients. Ann Rehabil Med. 2024 Aug;48(4):239-248. doi: 10.5535/arm.240005. Epub 2024 Aug 30. PMID 39210749
• Lee CL, Wang PC, Chen YL, Chen ZY, Uen CC, Lai HY, Shiao CC. Comparisons of Intradialytic Exercise Versus Home-Based Exercise in Hemodialysis Patients: A Narrative Review. Biomedicines. 2024 Oct 16;12(10):2364. doi: 10.3390/biomedicines12102364. PMID 39457675
• Zou ZH, Zhang JQ, Yi ZH, Chen X, Qing W. Effects of intradialytic exercise on frailty in maintenance hemodialysis patients: a systematic review and meta-analysis. Front Physiol. 2025 Nov 6;16:1600219. doi: 10.3389/fphys.2025.1600219. eCollection 2025. PMID 41281915
• Sepehri S, Sheikhhoseini R, Piri H, Sayyadi P. The effect of various therapeutic exercises on forward head posture, rounded shoulder, and hyperkyphosis among people with upper crossed syndrome: a systematic review and meta-analysis. BMC Musculoskelet Disord. 2024 Feb 1;25(1):105. doi: 10.1186/s12891-024-07224-4. PMID 38302926
• Mylonas K, Chatzis G, Makrypidi V, Chrysanthopoulos G, Gkrilias P, Tsekoura M, Billis E, Tsepis E, Tsirogiannis G, Fousekis K. Reliability of photogrammetric evaluation of the craniovertebral angle, swayback posture, and knee hyperextension in university students. J Phys Ther Sci. 2025 Apr;37(4):171-175. doi: 10.1589/jpts.37.171. Epub 2025 Apr 1. PMID 40171184
• Nepomuceno APFA, Cury AC, Pinheiro LSP, Sabino GS, Souza TR, Fonseca ST, Ocarino JM, Resende RA. Validity, reliability, and clinical usefulness of instruments for measuring thoracic kyphosis: a systematic review and meta-analysis. Braz J Phys Ther. 2025 Sep-Oct;29(5):101246. doi: 10.1016/j.bjpt.2025.101246. Epub 2025 Aug 7. PMID 40780025

Identifiers

NCT: NCT07720401 · PA26HD-2-03

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗